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<meta name="description" content="Lua 字符串 字符串或串(String)是由数字、字母、下划线组成的一串字符。 Lua 语言中字符串可以使用以下三种方式来表示：  单引号间的一串字符。 双引号间的一串字符。 [[ 与 ]] 间的一串字符。  以上三种方式的字符串实例如下：  实例 [mycode4 type=&#039;lua&#039;] string1 = &#039;Lua&#039; print(&#039;\&#039;字符串 1 是\&#039;&#03..">
		
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			<h1>Lua 字符串</h1>
<p>字符串或串(String)是由数字、字母、下划线组成的一串字符。</p>
<p>Lua 语言中字符串可以使用以下三种方式来表示：</p>
<ul>
<li>单引号间的一串字符。</li>
<li>双引号间的一串字符。</li>
<li><strong>[[</strong> 与 <strong>]]</strong> 间的一串字符。</li>
</ul>
<p>以上三种方式的字符串实例如下：</p>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
string1 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;Lua&quot;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;<span style="color: #000099; font-weight: bold;">\&quot;</span>字符串 1 是<span style="color: #000099; font-weight: bold;">\&quot;</span>&quot;</span><span style="color: #Gray;">,</span>string1<span style="color: Olive;">&#41;</span><br />
string2 <span style="color: #Gray;">=</span> <span style="color: #a11;">'runoob.com'</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;字符串 2 是&quot;</span><span style="color: #Gray;">,</span>string2<span style="color: Olive;">&#41;</span><br />
<br />
string3 <span style="color: #Gray;">=</span> <span style="color: #a50; font-style: italic;">[[&quot;Lua 教程&quot;]]</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;字符串 3 是&quot;</span><span style="color: #Gray;">,</span>string3<span style="color: Olive;">&#41;</span><br />
</div></div>

<p>以上代码执行输出结果为：</p>
<pre>
"字符串 1 是"&nbsp;&nbsp;&nbsp;&nbsp;Lua
字符串 2 是&nbsp;&nbsp;&nbsp;&nbsp;runoob.com
字符串 3 是&nbsp;&nbsp;&nbsp;&nbsp;"Lua 教程"
</pre>
<p>转义字符用于表示不能直接显示的字符，比如后退键，回车键，等。如在字符串转换双引号可以使用 "\""。</p>
<p>所有的转义字符和所对应的意义：</p>
<table log-set-param="table_view" class="reference"><tbody><tr><td><div class="para">转义字符</div>
</td><td><div class="para">意义</div>
</td><td><div class="para">ASCII码值（十进制）</div>
</td></tr><tr><td><div class="para">\a</div>
</td><td><div class="para">响铃(BEL)</div>
</td><td><div class="para">007</div>
</td></tr><tr><td><div class="para">\b</div>
</td><td><div class="para">退格(BS) ，将当前位置移到前一列</div>
</td><td><div class="para">008</div>
</td></tr><tr><td><div class="para">\f</div>
</td><td><div class="para">换页(FF)，将当前位置移到下页开头</div>
</td><td><div class="para">012</div>
</td></tr><tr><td><div class="para">\n</div>
</td><td><div class="para">换行(LF) ，将当前位置移到下一行开头</div>
</td><td><div class="para">010</div>
</td></tr><tr><td><div class="para">\r</div>
</td><td><div class="para">回车(CR) ，将当前位置移到本行开头</div>
</td><td><div class="para">013</div>
</td></tr><tr><td><div class="para">\t</div>
</td><td><div class="para">水平制表(HT) （跳到下一个TAB位置）</div>
</td><td><div class="para">009</div>
</td></tr><tr><td><div class="para">\v</div>
</td><td><div class="para">垂直制表(VT)</div>
</td><td><div class="para">011</div>
</td></tr><tr><td><div class="para">\\</div>
</td><td><div class="para">代表一个反斜线字符''\'</div>
</td><td><div class="para">092</div>
</td></tr><tr><td><div class="para">\'</div>
</td><td><div class="para">代表一个单引号（撇号）字符</div>
</td><td><div class="para">039</div>
</td></tr><tr><td><div class="para">\"</div>
</td><td><div class="para">代表一个双引号字符</div>
</td><td><div class="para">034</div>
</td></tr><tr><td><div class="para">\0</div>
</td><td><div class="para">空字符(NULL)</div>
</td><td><div class="para">000</div>
</td></tr><tr><td><div class="para">\ddd</div>
</td><td><div class="para">1到3位八进制数所代表的任意字符</div>
</td><td><div class="para">三位八进制</div>
</td></tr><tr><td><div class="para">\xhh</div>
</td><td><div class="para">1到2位十六进制所代表的任意字符</div>
</td><td><div class="para">二位十六进制</div>
</td></tr></tbody></table>
<hr>
<h2>字符串操作</h2>
<p>Lua 提供了很多的方法来支持字符串的操作：</p>
<table class="reference">
<tbody><tr><th style="width:5%">序号</th><th>方法 &amp; 用途</th></tr>
<tr><td>1</td><td><b>string.upper(argument):</b><br>字符串全部转为大写字母。</td></tr>
<tr><td>2</td><td><b>string.lower(argument):</b><br>字符串全部转为小写字母。</td></tr>
<tr><td>3</td><td><b>string.gsub(mainString,findString,replaceString,num)</b><p>在字符串中替换。</p>
mainString 为要操作的字符串， findString 为被替换的字符，replaceString 要替换的字符，num 替换次数（可以忽略，则全部替换），如：	
<pre>
&gt; string.gsub("aaaa","a","z",3);
zzza&nbsp;&nbsp;&nbsp;&nbsp;3
</pre>
</td></tr>
<tr><td>4</td><td><b>string.find (str, substr, [init, [plain]])</b><br>
<p>在一个指定的目标字符串 str 中搜索指定的内容 substr，如果找到了一个匹配的子串，就会返回这个子串的起始索引和结束索引，不存在则返回 nil。</p>
<p><span class="marked">init</span> 指定了搜索的起始位置，默认为 1，可以一个负数，表示从后往前数的字符个数。</p>
<p><span class="marked">plain</span> 表示是否使用简单模式，默认为 false，true 只做简单的查找子串的操作，false 表示使用使用正则模式匹配。</p>
<p>以下实例查找字符串 "Lua" 的起始索引和结束索引位置：</p>
<pre>
&gt; string.find("Hello Lua user", "Lua", 1) 
7&nbsp;&nbsp;&nbsp;&nbsp;9
</pre>
</td></tr>
<tr><td>5</td><td><b>string.reverse(arg)</b><br>字符串反转<pre>
&gt; string.reverse("Lua")
auL</pre></td></tr>
<tr><td>6</td><td><b>string.format(...)</b><br>返回一个类似printf的格式化字符串
<pre>
&gt; string.format("the value is:%d",4)
the value is:4
</pre></td></tr>
<tr><td>7</td><td><b>string.char(arg) 和 string.byte(arg[,int])</b><br>char 将整型数字转成字符并连接， byte 转换字符为整数值(可以指定某个字符，默认第一个字符)。
<pre>
&gt; string.char(97,98,99,100)
abcd
&gt; string.byte("ABCD",4)
68
&gt; string.byte("ABCD")
65
&gt;
</pre></td></tr>
<tr><td>8</td><td><b>string.len(arg)</b><br>计算字符串长度。
<pre>
string.len("abc")
3
</pre></td></tr>
<tr><td>9</td><td><b>string.rep(string, n)</b><br>返回字符串string的n个拷贝
<pre>
&gt; string.rep("abcd",2)
abcdabcd
</pre>

</td></tr>
<tr><td>10</td><td><b>..</b><br>链接两个字符串
<pre>
&gt; print("www.runoob.".."com")
www.runoob.com
</pre>
</td></tr>

<tr><td>11</td><td><b>string.gmatch(str, pattern)</b><br>返回一个迭代器函数，每一次调用这个函数，返回一个在字符串 str 找到的下一个符合 pattern 描述的子串。如果参数 pattern 描述的字符串没有找到，迭代函数返回nil。
<pre>
&gt; for word in string.gmatch("Hello Lua user", "%a+") do print(word) end
Hello
Lua
user
</pre>
</td></tr>
<tr><td>12</td><td><b>string.match(str, pattern, init)</b><br>string.match()只寻找源字串str中的第一个配对. 参数init可选, 指定搜寻过程的起点, 默认为1。
<br>
在成功配对时, 函数将返回配对表达式中的所有捕获结果; 如果没有设置捕获标记, 则返回整个配对字符串. 当没有成功的配对时, 返回nil。
<pre>
&gt; = string.match("I have 2 questions for you.", "%d+ %a+")
2 questions

&gt; = string.format("%d, %q", string.match("I have 2 questions for you.", "(%d+) (%a+)"))
2, "questions"
</pre>
</td></tr>
</tbody></table>
<h3>字符串截取</h3><p>
字符串截取使用 sub() 方法。</p>
<p>string.sub() 用于截取字符串，原型为：</p>

<pre>string.sub(s, i [, j])</pre>

<p>参数说明：</p>
<ul><li>
s：要截取的字符串。</li><li>
i：截取开始位置。</li><li>
j：截取结束位置，默认为 -1，最后一个字符。</li></ul>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
<br />
<span style="color: #a50; font-style: italic;">-- 字符串</span><br />
<span style="color: Green; font-weight: bold;">local</span> sourcestr <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;prefix--runoobgoogletaobao--suffix&quot;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;<span style="color: #000099; font-weight: bold;">\n</span>原始字符串&quot;</span><span style="color: #Gray;">,</span> <span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%q&quot;</span><span style="color: #Gray;">,</span> sourcestr<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 截取部分，第4个到第15个</span><br />
<span style="color: Green; font-weight: bold;">local</span> first_sub <span style="color: #Gray;">=</span> <span style="color: #05a;">string.sub</span><span style="color: Olive;">&#40;</span>sourcestr<span style="color: #Gray;">,</span> <span style="color: Maroon;">4</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">15</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;<span style="color: #000099; font-weight: bold;">\n</span>第一次截取&quot;</span><span style="color: #Gray;">,</span> <span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%q&quot;</span><span style="color: #Gray;">,</span> first_sub<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 取字符串前缀，第1个到第8个</span><br />
<span style="color: Green; font-weight: bold;">local</span> second_sub <span style="color: #Gray;">=</span> <span style="color: #05a;">string.sub</span><span style="color: Olive;">&#40;</span>sourcestr<span style="color: #Gray;">,</span> <span style="color: Maroon;">1</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">8</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;<span style="color: #000099; font-weight: bold;">\n</span>第二次截取&quot;</span><span style="color: #Gray;">,</span> <span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%q&quot;</span><span style="color: #Gray;">,</span> second_sub<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 截取最后10个</span><br />
<span style="color: Green; font-weight: bold;">local</span> third_sub <span style="color: #Gray;">=</span> <span style="color: #05a;">string.sub</span><span style="color: Olive;">&#40;</span>sourcestr<span style="color: #Gray;">,</span> <span style="color: #Gray;">-</span><span style="color: Maroon;">10</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;<span style="color: #000099; font-weight: bold;">\n</span>第三次截取&quot;</span><span style="color: #Gray;">,</span> <span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%q&quot;</span><span style="color: #Gray;">,</span> third_sub<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 索引越界，输出原始字符串</span><br />
<span style="color: Green; font-weight: bold;">local</span> fourth_sub <span style="color: #Gray;">=</span> <span style="color: #05a;">string.sub</span><span style="color: Olive;">&#40;</span>sourcestr<span style="color: #Gray;">,</span> <span style="color: #Gray;">-</span><span style="color: Maroon;">100</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;<span style="color: #000099; font-weight: bold;">\n</span>第四次截取&quot;</span><span style="color: #Gray;">,</span> <span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%q&quot;</span><span style="color: #Gray;">,</span> fourth_sub<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
</div></div>
<p>以上代码执行结果为：</p><pre>
原始字符串&nbsp;&nbsp;&nbsp;&nbsp;"prefix--runoobgoogletaobao--suffix"

第一次截取&nbsp;&nbsp;&nbsp;&nbsp;"fix--runoobg"

第二次截取&nbsp;&nbsp;&nbsp;&nbsp;"prefix--"

第三次截取&nbsp;&nbsp;&nbsp;&nbsp;"ao--suffix"

第四次截取&nbsp;&nbsp;&nbsp;&nbsp;"prefix--runoobgoogletaobao--suffix"</pre>
<h3>字符串大小写转换</h3>
<p>以下实例演示了如何对字符串大小写进行转换：</p>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
string1 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;Lua&quot;</span><span style="color: #Gray;">;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.upper</span><span style="color: Olive;">&#40;</span>string1<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.lower</span><span style="color: Olive;">&#40;</span>string1<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
</div></div>

<p>以上代码执行结果为：</p>
<pre>
LUA
lua
</pre>
<h3>字符串查找与反转</h3>
<p>以下实例演示了如何对字符串进行查找与反转操作：</p>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
<span style="color: #05a;">string</span> <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;Lua Tutorial&quot;</span><br />
<span style="color: #a50; font-style: italic;">-- 查找字符串</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.find</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string</span><span style="color: #Gray;">,</span><span style="color: #a11;">&quot;Tutorial&quot;</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
reversedString <span style="color: #Gray;">=</span> <span style="color: #05a;">string</span><span style="color: #Gray;">.</span>reverse<span style="color: Olive;">&#40;</span><span style="color: #05a;">string</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;新字符串为&quot;</span><span style="color: #Gray;">,</span>reversedString<span style="color: Olive;">&#41;</span><br />
</div></div>

<p>以上代码执行结果为：</p>
<pre>
5&nbsp;&nbsp;&nbsp;&nbsp;12
新字符串为&nbsp;&nbsp;&nbsp;&nbsp;lairotuT auL
</pre>
<h3>字符串格式化</h3>
<p>Lua 提供了 <span class="marked">string.format()</span> 函数来生成具有特定格式的字符串, 函数的第一个参数是格式 , 之后是对应格式中每个代号的各种数据。</p><p>由于格式字符串的存在, 使得产生的长字符串可读性大大提高了。这个函数的格式很像 C 语言中的 printf()。</p>
<p>以下实例演示了如何对字符串进行格式化操作：</p>
<p>格式字符串可能包含以下的转义码:
</p><ul><li>
%c - 接受一个数字, 并将其转化为ASCII码表中对应的字符</li><li>
%d, %i - 接受一个数字并将其转化为有符号的整数格式</li><li>
%o - 接受一个数字并将其转化为八进制数格式</li><li>
%u - 接受一个数字并将其转化为无符号整数格式</li><li>
%x - 接受一个数字并将其转化为十六进制数格式, 使用小写字母</li><li>
%X - 接受一个数字并将其转化为十六进制数格式, 使用大写字母</li><li>
%e - 接受一个数字并将其转化为科学记数法格式, 使用小写字母e</li><li>
%E - 接受一个数字并将其转化为科学记数法格式, 使用大写字母E</li><li>
%f - 接受一个数字并将其转化为浮点数格式</li><li>
%g(%G) - 接受一个数字并将其转化为%e(%E, 对应%G)及%f中较短的一种格式</li><li>
%q - 接受一个字符串并将其转化为可安全被Lua编译器读入的格式</li><li>
%s - 接受一个字符串并按照给定的参数格式化该字符串</li></ul>
<p>
为进一步细化格式, 可以在%号后添加参数. 参数将以如下的顺序读入:
</p><ul><li>
(1) 符号: 一个+号表示其后的数字转义符将让正数显示正号. 默认情况下只有负数显示符号.</li><li>
(2) 占位符: 一个0, 在后面指定了字串宽度时占位用. 不填时的默认占位符是空格.</li><li>
(3) 对齐标识: 在指定了字串宽度时, 默认为右对齐, 增加-号可以改为左对齐.</li><li>
(4) 宽度数值</li><li>
(5) 小数位数/字串裁切: 在宽度数值后增加的小数部分n, 若后接f(浮点数转义符, 如%6.3f)则设定该浮点数的小数只保留n位, 若后接s(字符串转义符, 如%5.3s)则设定该字符串只显示前n位.</li></ul>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
string1 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;Lua&quot;</span><br />
string2 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;Tutorial&quot;</span><br />
number1 <span style="color: #Gray;">=</span> <span style="color: Maroon;">10</span><br />
number2 <span style="color: #Gray;">=</span> <span style="color: Maroon;">20</span><br />
<span style="color: #a50; font-style: italic;">-- 基本字符串格式化</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;基本格式化 %s %s&quot;</span><span style="color: #Gray;">,</span>string1<span style="color: #Gray;">,</span>string2<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #a50; font-style: italic;">-- 日期格式化</span><br />
<span style="color: #05a;">date</span> <span style="color: #Gray;">=</span> <span style="color: Maroon;">2</span><span style="color: #Gray;">;</span> month <span style="color: #Gray;">=</span> <span style="color: Maroon;">1</span><span style="color: #Gray;">;</span> year <span style="color: #Gray;">=</span> <span style="color: Maroon;">2014</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;日期格式化 %02d/%02d/%03d&quot;</span><span style="color: #Gray;">,</span> <span style="color: #05a;">date</span><span style="color: #Gray;">,</span> month<span style="color: #Gray;">,</span> year<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #a50; font-style: italic;">-- 十进制格式化</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%.4f&quot;</span><span style="color: #Gray;">,</span><span style="color: Maroon;">1</span><span style="color: #Gray;">/</span><span style="color: Maroon;">3</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
</div></div>

<p>以上代码执行结果为：</p>
<pre>
基本格式化 Lua Tutorial
日期格式化 02/01/2014
0.3333
</pre>
<p>其他例子：</p>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%c&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">83</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出S</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%+d&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">17.0</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span style="color: #a50; font-style: italic;">-- 输出+17</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%05d&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">17</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出00017</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%o&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">17</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出21</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%u&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">3.14</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出3</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%x&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">13</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出d</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%X&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">13</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出D</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%e&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">1000</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出1.000000e+03</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%E&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">1000</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出1.000000E+03</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%6.3f&quot;</span><span style="color: #Gray;">,</span> <span style="color: Maroon;">13</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span style="color: #a50; font-style: italic;">-- 输出13.000</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%q&quot;</span><span style="color: #Gray;">,</span> <span style="color: #a11;">&quot;One<span style="color: #000099; font-weight: bold;">\n</span>Two&quot;</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出&quot;One\</span><br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 　　Two&quot;</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%s&quot;</span><span style="color: #Gray;">,</span> <span style="color: #a11;">&quot;monkey&quot;</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出monkey</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%10s&quot;</span><span style="color: #Gray;">,</span> <span style="color: #a11;">&quot;monkey&quot;</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp; <span style="color: #a50; font-style: italic;">-- 输出 &nbsp; &nbsp;monkey</span><br />
<span style="color: #05a;">string.format</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;%5.3s&quot;</span><span style="color: #Gray;">,</span> <span style="color: #a11;">&quot;monkey&quot;</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp; &nbsp; &nbsp;<span style="color: #a50; font-style: italic;">-- 输出 &nbsp;mon</span><br />
</div></div>

<h3>字符与整数相互转换</h3>
<p>以下实例演示了字符与整数相互转换：</p>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
<span style="color: #a50; font-style: italic;">-- 字符转换</span><br />
<span style="color: #a50; font-style: italic;">-- 转换第一个字符</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.byte</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;Lua&quot;</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #a50; font-style: italic;">-- 转换第三个字符</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.byte</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;Lua&quot;</span><span style="color: #Gray;">,</span><span style="color: Maroon;">3</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #a50; font-style: italic;">-- 转换末尾第一个字符</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.byte</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;Lua&quot;</span><span style="color: #Gray;">,-</span><span style="color: Maroon;">1</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #a50; font-style: italic;">-- 第二个字符</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.byte</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;Lua&quot;</span><span style="color: #Gray;">,</span><span style="color: Maroon;">2</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #a50; font-style: italic;">-- 转换末尾第二个字符</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.byte</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;Lua&quot;</span><span style="color: #Gray;">,-</span><span style="color: Maroon;">2</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 整数 ASCII 码转换为字符</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.char</span><span style="color: Olive;">&#40;</span><span style="color: Maroon;">97</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
</div></div>

<p>以上代码执行结果为：</p>
<pre>
76
97
97
117
117
a
</pre>
<h3>其他常用函数</h3>
<p>以下实例演示了其他字符串操作，如计算字符串长度，字符串连接，字符串复制等：</p>

<div class="example"><h2 class="example">实例</h2> <div class="example_code">
string1 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;www.&quot;</span><br />
string2 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;runoob&quot;</span><br />
string3 <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;.com&quot;</span><br />
<span style="color: #a50; font-style: italic;">-- 使用 .. 进行字符串连接</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;连接字符串&quot;</span><span style="color: #Gray;">,</span>string1<span style="color: #Gray;">..</span>string2<span style="color: #Gray;">..</span>string3<span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 字符串长度</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #a11;">&quot;字符串长度 &quot;</span><span style="color: #Gray;">,</span><span style="color: #05a;">string.len</span><span style="color: Olive;">&#40;</span>string2<span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><br />
<br />
<span style="color: #a50; font-style: italic;">-- 字符串复制 2 次</span><br />
repeatedString <span style="color: #Gray;">=</span> <span style="color: #05a;">string.rep</span><span style="color: Olive;">&#40;</span>string2<span style="color: #Gray;">,</span><span style="color: Maroon;">2</span><span style="color: Olive;">&#41;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span>repeatedString<span style="color: Olive;">&#41;</span><br />
</div></div>

<p>以上代码执行结果为：</p>
<pre>
连接字符串&nbsp;&nbsp;&nbsp;&nbsp;www.runoob.com
字符串长度 &nbsp;&nbsp;&nbsp;&nbsp;6
runoobrunoob
</pre><h3>匹配模式</h3>
<p>Lua 中的匹配模式直接用常规的字符串来描述。 它用于模式匹配函数 <strong>string.find, string.gmatch, string.gsub, string.match</strong>。 </p>
<p>
你还可以在模式串中使用字符类。</p><p>字符类指可以匹配一个特定字符集合内任何字符的模式项。比如，字符类 <strong>%d</strong> 匹配任意数字。所以你可以使用模式串  <span class="marked">%d%d/%d%d/%d%d%d%d</span> 搜索 <strong>dd/mm/yyyy</strong> 格式的日期：</p>
<div class="example"><h2 class="example">实例</h2> <div class="example_code">
s <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;Deadline is 30/05/1999, firm&quot;</span><br />
<span style="color: #05a;">date</span> <span style="color: #Gray;">=</span> <span style="color: #a11;">&quot;%d%d/%d%d/%d%d%d%d&quot;</span><br />
<span style="color: #05a;">print</span><span style="color: Olive;">&#40;</span><span style="color: #05a;">string.sub</span><span style="color: Olive;">&#40;</span>s<span style="color: #Gray;">,</span> <span style="color: #05a;">string.find</span><span style="color: Olive;">&#40;</span>s<span style="color: #Gray;">,</span> <span style="color: #05a;">date</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span><span style="color: Olive;">&#41;</span> &nbsp; &nbsp;<span style="color: #a50; font-style: italic;">--&gt; 30/05/1999</span><br />
</div></div>
<p>
下面的表列出了Lua支持的所有字符类：
</p>
<p>单个字符(除 <strong>^$()%.[]*+-?</strong> 外): 与该字符自身配对</p>
<ul><li>
.(点): 与任何字符配对</li><li>
%a: 与任何字母配对</li><li>
%c: 与任何控制符配对(例如\n)</li><li>
%d: 与任何数字配对</li><li>
%l: 与任何小写字母配对</li><li>
%p: 与任何标点(punctuation)配对</li><li>
%s: 与空白字符配对</li><li>
%u: 与任何大写字母配对</li><li>
%w: 与任何字母/数字配对</li><li>
%x: 与任何十六进制数配对</li><li>
%z: 与任何代表0的字符配对</li><li>
%x(此处x是非字母非数字字符): 与字符x配对. 主要用来处理表达式中有功能的字符(^$()%.[]*+-?)的配对问题, 例如%%与%配对</li><li>
[数个字符类]: 与任何[]中包含的字符类配对. 例如[%w_]与任何字母/数字, 或下划线符号(_)配对</li><li>
[^数个字符类]: 与任何不包含在[]中的字符类配对. 例如[^%s]与任何非空白字符配对</li></ul>
<p>当上述的字符类用大写书写时, 表示与非此字符类的任何字符配对. 例如, %S表示与任何非空白字符配对.例如，'%A'非字母的字符:</p>
<pre>
&gt; print(string.gsub("hello, up-down!", "%A", "."))
hello..up.down.&nbsp;&nbsp;&nbsp;&nbsp;4
</pre>
<p>数字4不是字符串结果的一部分，他是gsub返回的第二个结果，代表发生替换的次数。</p>
<p>在模式匹配中有一些特殊字符，他们有特殊的意义，Lua中的特殊字符如下：</p><pre>
( ) . % + - * ? [ ^ $</pre><p>
'%' 用作特殊字符的转义字符，因此 '%.' 匹配点；'%%' 匹配字符 '%'。转义字符 '%'不仅可以用来转义特殊字符，还可以用于所有的非字母的字符。</p>
<p><b>模式条目可以是：</b></p>
<ul>

<li>
单个字符类匹配该类别中任意单个字符；
</li>

<li>
单个字符类跟一个 '<code>*</code>'，
将匹配零或多个该类的字符。
这个条目总是匹配尽可能长的串；
</li>

<li>
单个字符类跟一个 '<code>+</code>'，
将匹配一或更多个该类的字符。
这个条目总是匹配尽可能长的串；
</li>

<li>
单个字符类跟一个 '<code>-</code>'，
将匹配零或更多个该类的字符。
和 '<code>*</code>' 不同，
这个条目总是匹配尽可能短的串；
</li>

<li>
单个字符类跟一个 '<code>?</code>'，
将匹配零或一个该类的字符。
只要有可能，它会匹配一个；
</li>

<li>
<code>%<em>n</em></code>，
这里的 <em>n</em> 可以从 1 到 9；
这个条目匹配一个等于 <em>n</em> 号捕获物（后面有描述）的子串。
</li>

<li>
<code>%b<em>xy</em></code>，
这里的 <em>x</em> 和 <em>y</em> 是两个明确的字符；
这个条目匹配以 <em>x</em> 开始 <em>y</em> 结束，
且其中 <em>x</em> 和 <em>y</em> 保持 <em>平衡</em> 的字符串。
意思是，如果从左到右读这个字符串，对每次读到一个
<em>x</em> 就 <em>+1</em> ，读到一个 <em>y</em> 就 <em>-1</em>，
最终结束处的那个 <em>y</em> 是第一个记数到 0 的 <em>y</em>。
举个例子，条目 <code>%b()</code> 可以匹配到括号平衡的表达式。
</li>

<li>
<code>%f[<em>set</em>]</code>，
指 <em>边境模式</em>；
这个条目会匹配到一个位于 <em>set</em> 内某个字符之前的一个空串，
且这个位置的前一个字符不属于 <em>set</em> 。
集合 <em>set</em> 的含义如前面所述。
匹配出的那个空串之开始和结束点的计算就看成该处有个字符
'<code>\0</code>' 一样。
</li>

</ul><p><b>模式：</b><p>
<em>模式</em> 指一个模式条目的序列。
在模式最前面加上符号 '<code>^</code>' 将锚定从字符串的开始处做匹配。
在模式最后面加上符号 '<code>$</code>' 将使匹配过程锚定到字符串的结尾。
如果 '<code>^</code>' 和 '<code>$</code>' 出现在其它位置，它们均没有特殊含义，只表示自身。

</p>



<p><b>捕获：</b><p>
模式可以在内部用小括号括起一个子模式；
这些子模式被称为 <em>捕获物</em>。
当匹配成功时，由 <em>捕获物</em> 匹配到的字符串中的子串被保存起来用于未来的用途。
捕获物以它们左括号的次序来编号。
例如，对于模式 <code>"(a*(.)%w(%s*))"</code> ，
字符串中匹配到 <code>"a*(.)%w(%s*)"</code> 的部分保存在第一个捕获物中
（因此是编号 1 ）；
由 "<code>.</code>" 匹配到的字符是 2 号捕获物，
匹配到 "<code>%s*</code>" 的那部分是 3 号。</p>


<p>
作为一个特例，空的捕获 <code>()</code> 将捕获到当前字符串的位置（它是一个数字）。
例如，如果将模式 <code>"()aa()"</code> 作用到字符串
<code>"flaaap"</code> 上，将产生两个捕获物：
3 和 5 。</p>			<!-- 其他扩展 -->
						
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<div id="postcomments"  style="display:none;" >
	<ol class="commentlist">
		<li class="comment even thread-even depth-1" id="comment-14201"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;二牛</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;248***0454@qq.com</p></div><div id="runoobvote-id-14201" data-commid = "14201" class="upvotejs"><a class="upvote"></a> <span class="count">18</span></div></div><div class="comt-main" id="div-comment-14201"><p>将阿拉伯数字转换为语文汉字数字：
</p><pre>
local function NumToCN(num)
    local size = #tostring(num)
    local CN = ""
    local StrCN = {"一","二","三","四","五","六","七","八","九"}
    for i = 1 , size do
        CN = CN .. StrCN[tonumber(string.sub(tostring(num), i , i))]
    end
    return CN
end
print(NumToCN(56665))</pre><div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">二牛</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;二牛</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;248***0454@qq.com</p></div></span>6年前 (2017-07-18)</div></div></li><!-- #comment-## -->
<li class="comment odd alt thread-odd thread-alt depth-1" id="comment-16237"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;二牛</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;248***0454@qq.com</p><p><i class="fa fa-external-link" aria-hidden="true"></i> <a rel="nofollow" target="_blank" href="https://zhidao.baidu.com/question/1754609699341651788.html">&nbsp;&nbsp;参考地址</a></p></div><div id="runoobvote-id-16237" data-commid = "16237" class="upvotejs"><a class="upvote"></a> <span class="count">10</span></div></div><div class="comt-main" id="div-comment-16237"><p>移除中文部分：</p><pre>function StrSplit(inputstr, sep)
    if sep == nil then
      sep = "%s"
    end
    local t={}
    local i=1
    for str in string.gmatch(inputstr, "([^"..sep.."]+)") do
       t[i] = str
       i = i + 1
    end
    return t
end
local a = "23245023496830,汉字。。。。"
local b = ":"
b = StrSplit(a,",")
print(b[1])

----輸出: 23245023496830</pre><div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">二牛</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;二牛</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;248***0454@qq.com</p><p><i class="fa fa-external-link" aria-hidden="true"></i> <a rel="nofollow" target="_blank" href="https://zhidao.baidu.com/question/1754609699341651788.html">&nbsp;&nbsp;参考地址</a></p></div></span>6年前 (2017-08-11)</div></div></li><!-- #comment-## -->
<li class="comment even thread-even depth-1" id="comment-25854"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;wb070815</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;109***2751@qq.com</p></div><div id="runoobvote-id-25854" data-commid = "25854" class="upvotejs"><a class="upvote"></a> <span class="count">7</span></div></div><div class="comt-main" id="div-comment-25854"><p>去除字符串首尾的空格</p>
<pre>
function trim(s)
  return (string.gsub(s, "^%s*(.-)%s*$", "%1")) 
end
string1 = "   RUNOOB        "
string2 = trim(string1)
print(string2)</pre><div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">wb070815</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;wb070815</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;109***2751@qq.com</p></div></span>5年前 (2018-04-03)</div></div></li><!-- #comment-## -->
<li class="comment odd alt thread-odd thread-alt depth-1" id="comment-38427"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;tigersleepy</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;295***8832@qq.com</p></div><div id="runoobvote-id-38427" data-commid = "38427" class="upvotejs"><a class="upvote"></a> <span class="count">5</span></div></div><div class="comt-main" id="div-comment-38427"><p><strong>%f 的使用</strong></p>

<p>需求获取特殊边界的字符串。</p>

<p>举例："123 h123 hds45678 fdaga123ad  h123s"</p>

<p>需求：获取左边界为字母，右边界为空格的数字字符串。</p>

<p>1.获取所有带边界的数字串</p>


<pre>str1 =  "123 h123 hds45678 fdaga123ad  h123s"
string.gmatch(str1,"%D%d+%D")</pre>


<p>匹配结果：123  h123  s45678  a123a h123s</p>

<p>确定边界：左：%a   右：%s</p>

<pre>string.gmatch(str1,"%f[%A]%d+%f[%s]")</pre>

<pre>匹配结果：45678</pre><div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">tigersleepy</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;tigersleepy</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;295***8832@qq.com</p></div></span>4年前 (2018-12-28)</div></div></li><!-- #comment-## -->
<li class="comment even thread-even depth-1" id="comment-46453"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;scorlw</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;sco***@163.com</p></div><div id="runoobvote-id-46453" data-commid = "46453" class="upvotejs"><a class="upvote"></a> <span class="count">14</span></div></div><div class="comt-main" id="div-comment-46453"><p>string.gsub 函数替代是按照字节来替代的。如本例中:</p>

<pre>&gt; print(string.gsub("hello，up-down!", "%A", "."))</pre>
<p>输出为:</p>

<pre>hello..up.down. 4</pre>

<p>原因是 hello 后的逗号为中文全角，占两个字节，所以替换两次。</p><div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">scorlw</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;scorlw</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;sco***@163.com</p></div></span>4年前 (2019-09-04)</div></div></li><!-- #comment-## -->
<li class="comment odd alt thread-odd thread-alt depth-1" id="comment-52937"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;piyixia</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;a24***7036@qq.com</p></div><div id="runoobvote-id-52937" data-commid = "52937" class="upvotejs"><a class="upvote"></a> <span class="count">11</span></div></div><div class="comt-main" id="div-comment-52937"><p>string.gsub 函数替代是按照字节来替代的。如本例中:</p>

<pre>&gt; print(string.gsub("hello, up-down!", "%A", "."))</pre>
<p>输出为</p>：

<pre>hello..up.down. 4</pre><p>
原因是逗号后面是有一个空格的，占一个字节，所以 <strong>"， 空格  - ！ "</strong>，一个四个，共四次，前面说的中文逗号虽然也能解释，但是我觉得还是空格比较符合官方的意思。</p><div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">piyixia</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;piyixia</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;a24***7036@qq.com</p></div></span>3年前 (2020-04-22)</div></div></li><!-- #comment-## -->
<li class="comment even thread-even depth-1" id="comment-56247"><span class="comt-f">#0</span><div class="comt-avatar wrapper"><i style="font-size:36px;" class="fa fa-user-circle" aria-hidden="true"></i><div class="tooltip"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;TiAmo</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;576***486@qq.com</p></div><div id="runoobvote-id-56247" data-commid = "56247" class="upvotejs"><a class="upvote"></a> <span class="count">4</span></div></div><div class="comt-main" id="div-comment-56247"><p><strong>string.match(str, pattern, init)</strong></p>

<pre>string.match("I have 2 questions for you.", "%d+ %a+")</pre>
<p>如果 pattern 中单个匹配模式没有用小括号包含的话，最后会返回完整匹配的字符串。</p>

<p>例如：</p>

<pre>c,d=string.match("I have 23 questions for you.", "%d+ %a+")
print(c)        --&gt;23  questions
print(type(c))  --&gt;string
print(d)        --&gt;nil 空的
print(type(d))  --&gt;nil 空的</pre><p>
如果 pattern中 每个匹配模式用小括号包含的话，最后会按照多返回值的方式，被捕获到。</p>

<p>例如：</p>

<pre>c,d=string.match("I have 23 questions for you.", "(%d+) (%a+)")
print(c)        --&gt;23
print(type(c))  --&gt;string 即使是%d 最后也仍是string
print(d)        --&gt;questions
print(type(d))  --&gt;string</pre><p>
这样的话就可以用 format 来格式化输出了。</p>

string.format("%d, %q",c,d)  -->23,"questions"<div class="comt-meta wrapper"><span class="comt-author"><a target="_blank" href="javascript:;">TiAmo</a><div class="tooltip tooltip1"><p><i class="fa fa-user" aria-hidden="true"></i>&nbsp;&nbsp;&nbsp;TiAmo</p><p><i class="fa fa-envelope" aria-hidden="true"></i>&nbsp;&nbsp;576***486@qq.com</p></div></span>3年前 (2020-08-14)</div></div></li><!-- #comment-## -->
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